package com.chengxiaoxiao.web.servlet;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

//@WebServlet("/handler/VaildCode")
public class VaildCode extends HttpServlet {
    String[] code = new String[] { "a", "b", "c", "d", "e", "f", "g", "h", "i",
            "j", "k", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v",
            "w", "x", "y", "z", "0", "1", "2", "3", "4", "5", "6", "7", "8",
            "9", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L",
            "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y",
            "Z" };

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("image/jpeg");
        response.setHeader("Pragma", "No-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);

        // 在内存中创建图象
        int width = 80, height = 30;
        BufferedImage image = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);

        Graphics g = image.getGraphics();

        g.setColor(getRandColor(200, 250));
        g.fillRect(0, 0, width, height);

        g.setFont(new Font("Garamond", Font.PLAIN, 24));
        g.setColor(getRandColor(160, 200));
        g.drawRect(0, 0, width - 1, height - 1);

        // 随机产生155条干扰线
        g.setColor(getRandColor(160, 200));

        Random random = new Random();

        for (int i = 0; i < 155; i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x, y, x + xl, y + yl);
        }

        String sRand = "";
        for (int i = 0; i < 4; i++) {
            int index = random.nextInt(61);

            sRand += code[index];
            g.setColor(new Color(20 + random.nextInt(110), 20 + random
                    .nextInt(110), 20 + random.nextInt(110)));
            // 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
            g.drawString(code[index], 13 * i + 14, 23);
        }

        HttpSession session = request.getSession();
        session.setAttribute("vcode", sRand.toLowerCase());

        g.dispose();
        ImageIO.write(image, "JPEG", response.getOutputStream());

    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

    }

    Color getRandColor(int fc, int bc) {// 给定范围获得随机颜色
        Random random = new Random();
        if (fc > 255)
            fc = 255;
        if (bc > 255)
            bc = 255;
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);
    }
}
